Psoriasis is a chronic inflammatory skin disease that to this date is only insufficiently controlled by currently available treatments which can also come with severe, and sometimes life threatening side effects. In this application, we propose to create a new class of biologics drug for the treatment of this debilitating disease. We are proposing to formulate the immunomodulatory neuropeptide vasoactive intestinal peptide (VIP) into a long-acting formulation that will be tested as a drug candidate for the treatment of psoriasis. From preliminary experiments we know that our formulation can be injected subcutaneously (s.c.) which is of advantage for patients with severe disease, and we envision that it can be applied topically for less severe cases. During the Phase I of this project, we propose to synthesize a new batch of drug carrier that we used for the formulation of VIP in preliminary experiments. This formulation has increased in vivo half-life and provides better safety properties compared to unformulated VIP. In the proposed project, we will collect data about bioavailability of VIP after s.c. and topical administration, and, as VIP can decrease the arterial blood pressure, measure the blood pressure in the tail of VIP treated mice after topical administration. Blood pressure data already exists for s.c. administration of our VIP formulation. VIP has been shown to be efficacious in many animal models of chronic inflammatory conditions in which efficacy overlaps with efficacy for psoriasis; however, it has not been tested directly in models of psoriasis. We therefore also propose in this application to test efficacy of our long-acting VIP formulation after s.c. administration and topical application in a mouse model of psoriasis. If Phase I is successful, we are planning to conduct a formal toxicity study during Phase II, further develop the topical formulation and file a investigational new drug application with the FDA at the end of Phase II.